Every turn of the breeze carries the acrid smell of coal. Here, in Greymouth, one of a string of small mining towns on the west coast of New Zealand's South Island it is normally a reminder of the region's economic well-spring, daily proof that the damp hand of winter is being kept at bay. Today it is a reminder that coalmining remains, everywhere, even in the newest mines in the world, a hazardous occupation.

Behind the windows of the neat wooden cottages, families are trying to keep the flame of hope alive in the face of an increasingly bleak prognosis after the huge gas explosion which ripped through the Pike River mine.

For five days there has been neither sight nor sound nor sign that any of the 29 missing miners caught in the mine are alive. Survivors will certainly have run out of food and, while water and a compressed air line are still available, their lights will have long gone dead.

The situation below ground, since Friday's explosion, remains, in the words of New Zealand's police commissioner, Howard Broad, so "extremely dangerous'" rescue teams are unable to enter the mine.

Above ground, still they hope. Lawrie Drew's son Zen, 21, is one of the missing. "I was bulletproof when I was his age and I know a lot of them down there are too … Those boys will do the best they can to stay alive to come out to us," he said.

Sonya Rockhouse is one of the few to have had a moment of glorious relief since the explosion. Her son, Daniel, 24, was one of two to limp out of the mine on Friday. But there are no celebrations at home; Daniel's brother, Ben, 21, remains below. "We're coping because we have to," she said. Her former husband, Neville, is the mine's safety and training manager. "When you have child you just never give up on them, it doesn't enter my head."

Those with longer memories are more tempered. For Harold Newby, 87, a third-generation miner who lost many friends when the nearby Strongman mine exploded in 1967 killing 19, the danger of mining has never seemed far away. "They bulldozed a big grave out," he recalled of the mass burial in Greymouth three days after that disaster.

Coal, discovered in 1848 here, is embedded in the coastal community's fabric. Everyone knows a miner and jobs underground carry "mana", or stature. Apart from good pay, miners receive 10 tonnes of coal a year.

No one wishes to break ranks and say publicly what so many think: anyone near the blast – and most of the 29 men were – must surely be dead. The rescue of 33 miners at the San José mine in the south of Chile was miraculous; finding these men alive would be a miracle.

The prime minister, John Key, confirmed today that assessment, calling the situation grave, preparing the nation for "possible loss of life".

Survival tales, such as that of the San José miners, have thrilled the world, but here, on South Island's west coast, settled by Celtic miners and immigrants from the English midlands in the 19th century, they are tempered by memory. Some 65 men and boys perished in 1896 when the Brunner mine exploded; Mt Davy was a mine that opened in 1997 but was shut a year later, after three men died in explosions. Accusations have been levelled at, and denied by Pike River, that this mine had high gas levels and was intrinsically dangerous.

Twice daily in Greymouth relatives enter a community hall for a briefing. Frustrations are boiling, exacerbated when dripping water made an investigating robot break down. "We're still in the same position we were in on the first night," said Drew. "They're going to have to be careful with some of the people because they might not know how to control themselves. That's getting pretty evident."

Tony Kokshoorn, mayor of Grey district, said: "The last five days have been traumatic and gut-wrenching and heartbreaking … It's incredible to see so many people in such a terrible position, waiting to get a resolution … Those affected families are actually screaming for someone to tell them one way or another the final outcome of this." Until then, he added, they were "going to hang on to every hope".